Civil War 2013: Photographs From the Grisly American Conflict | The New ...

The North had more men and war materials than the South.

At the beginning of the Civil War, 22 million people lived in the North and 9 million people (nearly 4 million of whom were slaves) lived in the South.  

The North also had more money, more factories, more horses, more railroads, and more farmland. On paper, these advantages made the United States much more powerful than the Confederate States.  

However, the Confederates were fighting defensively on territory that they knew well. They also had the advantage of the sheer size of the Southern Confederacy. Which meant that the northern armies would have to capture and hold vast quantities of land across the south. 

Still, too, the Confederacy maintained some of the best ports in North America—including New Orleans, Charleston, Mobile, Norfolk, and Wilmington. Thus, the Confederacy was able to mount a stubborn resistance.